The subject matter disclosed herein relates to rotorcraft control systems and, more particularly, to rotorcraft control systems in which trailing-edge flaps are actively controlled. The invention herein does not limit itself to flaps and has applications with any active system with actuators and feedback in the rotating system of a helicopter, such as, but not limited to, flaps, slats, individual blade control, MiTEs, blowing, and flex surfaces.
Rotorcraft, such as, but not limited to, helicopters have included control systems using a swashplate for effectuating primary flight control. Although simple to implement, the swashplate control system suffers from several shortcomings, including large drag forces which significantly reduce energy efficiency, lack of higher harmonic control capability, and insufficient system redundancy. Trailing-edge flaps have, therefore, been used for purposes of higher harmonic control, that is, for reduction of noise and vibration. These flaps, often termed “active flaps,” are located on the trailing edges of rotor blades and have typically been driven by electromechanical actuators or solenoids.
Typically, active flap control has been achieved by way of analog control signals sent to the electromechanical actuators or solenoids. This analog control, however, been observed to lead to a lag in the response times along with underperformance of the electromechanical actuators or solenoids from the commanded/desired, including amplitude and waveform. These response differences among the actuators cause the active flap control to be unsuitable in the presence of external forces and needs to be corrected.